The malignant cells from a patient with cutaneous T cell lymphoma (CTCL) are clonal and share a distinct T cell receptor (TCR). The premise of this project is that anti-tumor immune responses can be generated by inoculation with TCR-DNA expression plasmids which encode the TCR gene segments specific for the malignant clone in a T cell lymphoma. This will be tested in an established murine model of T cell lymphoma where the subcutaneous injection of the 2B4.11 T cell hybridoma cells into syngeneic mice results in tumor growth and decreased survival. A five year mentored program is proposed to study in mice the safety, efficacy, and various strategies designed to enhance DNA immunotherapy for T cell lymphoma. R. Tigelaar (expert in cellular immunology) will serve as sponsor, and A. Hayday (expert in molecular immunology), and J. Brandsma (expert in DNA immunization) will serve as cosponsors. Inoculations with TCR-DNA plasmids encoding portions of the alpha and beta chain of the 2B4 TCR will be assayed for their ability to elicit specific anti-tumor (anti-2B4.11) immune responses, as determined by in vitro proliferation and cytotoxicity assays. Inoculated mice will also be tested in vivo for their ability to resist 2B4.11 tumor challenge. The relative contributions of CD4+ and CD8+ cells to these responses will be determined using in vitro depleted cell populations, as well as in vivo depleted mice. Direct comparisons will assay the relevance of inoculation technique (intradermal vs. intramuscular vs. gene gun) and number of inoculations (single vs. multiple) on the ability of TCR-DNA plasmids to induce tumor immunity and protection as measured in the above assays. Once the optimal conditions for immunization in this model have been determined TCR-DNA plasmids will be tested for their ability to treat mice previously challenged with 2B4.11 hybridoma tumor. A variety of strategies designed to enhance the immunotherapeutic potential of TCR-DNA plasmid immunization will be examined, including: (1) co-inoculation with oligonucleotides containing CpG motifs, (2) co- or pre-injection with cytokine expression plasmids (i.e. GM-CSF, IL-12), (3) inoculation with chimeric TCR/cell-trafficking protein (i.e. ubiquitin, LAMP-1) plasmids, and (4) inoculation with dendritic cells transformed in vitro with TCR-DNA plasmids. Successfully targeting pathogenic populations of T cells via TCR-DNA immunization may lead to potential treatments for CTCL and other leukemias/lymphomas, systemic autoimmune processes such as multiple sclerosis, and transplant complications such as GVHD and organ transplant rejection.